As civilization______, more and more people have realized the importance of preserving rare animals from extinction.

What ______ to so many students coming to the school gate?

Yao Ming is generally ________ as the best basketball player in the world.

Noone has _____ been able to trace the author of the poem.

We are interested in the weather because it _____ us so directly ------ what we wear, what we do, and even how we feel.